Bug [3602534]: Test for XScreensaver last.
Bug [3602534]: Test for XScreensaver last.
Bug [3599928]: Use XkbKeycodeToKeysym if available.
Oops. Missed removing one line in last commit.
Bug [3599928]: Use XkbKeycodeToKeysym if available.
Merge trunk. 
Define some macros in tk.h which are needed by Tk as fallback, which might be removed from future tcl.h versions.
merge trunk